Patent GB-515173-A (GB)
Title: Improvements in or relating to the determination of the moisture content of sand and other materials
IPC: G01N9/36
Filed: 1938-05-26
Abstract: 515,173. Weighing-apparatus. STANCLIFFE, C. W., and WINGET, Ltd. May 26, 1938, Nos. 15750 and 34379. [Class 143] [Also in Group XX] Apparatus for use in the determination of the moisture content of wet material comprises weighing apparatus by which a sample of the wet material may be weighed in air and in water, counterbalance means calibrated as if the balancing effect were equivalent to that of a standard weight and having an actual balancing. effect equivalent to that of the corresponding weight when immersed in water, of dry material of the same specific gravity as the material to be tested and means, calibrated to denote the moisture content of the sample for restoring balance to the weighing apparatus when a sample of wet material of weight in air equal to the standard weight is immersed in water and opposed to these counterbalance means. As shown in Fig. 1 a scale beam 10 with suspended containers 18, 19 of equal weight carries a graduated beam 21 marked, (from a central zero) with a scale 22 indicating the percentage of moisture in a sample. A weight 23 is movable along the graduated scale. A compensating beam 24, also fixed to the scale beam, carries weights 25, 28. The weight 25 when against a stop 27, completes the balance of the containers when in air, but when against a stop 26 compensates for the apparent loss of weight of the container 18 when immersed in water in a tank 20. The weight 28 permits of final balance of the apparatus. In use, a sufficient quantity of wet substance is placed in the container 18 to balance a known weight placed in the container 19, the weight 23 being at zero and the weight 25 against the stop 27. The container 18 with the wet substance is immersed in the water tank 20 and the compensating weight 25 is moved to the stop 26. The weight in the container 19 is replaced by a weight equal to the weight in water of an equal quantity of the material under test. A number of these weights are provided corresponding. to materials of various specific gravities. The scale is restored to balance by moving the weight 23, the percentage of moisture in the sample being read off on the scale 22. In an alternative use, a dry master sample of material, for example sand, may be placed in the container 19 in order to balance the moist sample in the container 18. Both containers, with their contents are afterwards immersed in water and balance is effected by the poise 23 to give the percentage of moisture in the wet sand. In a modified apparatus, avoiding the use of loose weights, the sample of wet substance in air is balanced by an adjustable weight 31, Fig. 2, movable over scales 32, 33, the divisions of the scale 33 being reduced to an extent corresponding to the specific gravity of the average sand. The sample is weighed first in air and then in water in the manner described above, by adjustment of the weight 31 relative to the scale 32, the resetting of the weight along the . scale 33 and finally balancing by means of the percentage weight 35, the percentage of moisture then being given on the percentage scale 34. Minor order scales 32<1>, 33<1> may be provided. In a modification, Fig. 3, the scale beam carries a rotatable drum 48 bearing a number of scales 33 corresponding to materials of different specific gravities the appropriate scale being brought into co-operation with a sliding poise weight 51. Adjacent each of these scales is a percentage moisture scale 34. A weight-in-air scale is also provided on the drum. The moisture content is indicated on the relevent percentage moisture scale by effecting balance of the immersed sample by means of a poise weight 52 in a manner similar to that described above. The water tank 20 may be mounted on a lever for raising and lowering into and out of operative position. In order to determine the specific gravity of a sample, a specific gravity scale may be marked on the drum 48 in alignment with the weight-in-air scale. Using a standard quantity of dried material and immersing it in water the poise weight 51 when set at a predetermined mark balances material of standard specific gravity. If the sample departs from standard, balance is restored by adjusting the poise weight 52 on the specific gravity scale, and thereby indicating the specific gravity. The apparatus, Fig. 3, may be used also to determine the dry weight of an unknown quantity of wet sand.